Change composition of the program

 -Create Twiauth class.
    This class provide HTTP-Authrization header (for Twitter only).
		When this instance constract, take a user-name as a argument.
		If the user's access token have,use it for create header, else
		do token request process for obtain new access token and regist
		the token to local file.
 -Create main.cpp
    because created Twiauth class.